Cystic fibrosis (CF is a generalized exocrinopathy, whose basic defect is still unknown. Studies have been pursued to determine the reason for the abnormal serum fatty acid pattern in patients with CF and whether it represents a primary or secondary defect in this disease. Investigations on endocrine pancreatic function and the role it plays in the disorder have continued as well as studies of the exocrine function of this organ. Both are aimed at improving diagnostic methods and therapy of the malabsorption and glycosuria which are frequent complications of CF. Studies have been performed in 75 adult patients with this disease as well as in 232 from the literature of the incidence and manifest values of various complications which are significantly different from those of children and give rise at times to serious and at times emergent diagnostic and therapeutic problems. From patients at NIH as well as those gathered from various other CF centers throughout the country guidelines have been established for the use of assisted ventilation in all age groups in patients with CF.